Usually, a photosensitive resin plate is composed of a support material such as a plastic film, a metallic plate or the like, and a photosensitive resin layer formed on the surface of the support material. In order to make a photosensitive resin plate into an engraved plate such as a printing plate or the like, an original film is contacted on the surface of the photosensitive resin layer of the plate and an actinic light is irradiated to insolubilize the exposed part of the plate. Then, the non-exposed part is washed out with a solvent and thereafter, the plate is subjected to work up steps such as hydro-extracting, drying, post light exposure, etc. to form a printing plate or the like.
At present, a method mainly employed in the above plate making is a batch-wise method wherein each of the steps of washing out, hydro-extracting, drying and post light exposure are carried out separately by using different devices and, during the plate making, the plate is manually moved one step to another. For example, a photosensitive resin plate which has been exposed to light is set in a wash-out device where the non-exposed part thereof is is washed out. Thereafter it is moved to a drier by hand to dry the plate.
In order to constantly and quickly make photosensitive resin plates into engraved plates such as printing plates of stable high quality, a continuous and automatic plate making method has been required. In this regard, the development of a continuous plate making method has recently been started, wherein the above steps are continuously carried out while a photosensitive resin plate set on a surface of a belt or a so-called setting plate is moved horizontally. For carrying out this method, there has been developed a combination of devices wherein devices for each step such as washing out, hydro-extracting, drying, post light exposure and the like are arrayed in order of the steps on the same level parallel with the floor. The photosensitive resin plate is set on a chain or a setting plate fixed to a chain and the chain is driven intermittently or continuously.
However, in this combination of devices, there are drawbacks such as the requirement for a large space for arraying the devices, and poor working efficiency due to the long distance between openings for feeding and removing the photosensitive resin plate.
In order to save labor as much as possible and to reduce the space requirement, another continuous plate making method and a device thereof have been proposed (Japanese Patent Publication No. 21339/1980). In this method, a photosensitive resin plate is set on a peripheral surface of a cylindrical drum rotating intermittently and all the steps for plate making are completed during one rotation cycle of the drum.
However, in the above method and device, the rotation and stopping of the drum are repeated alternately at every angle of 120.degree. because of intermittent rotation and each step is carried out at the same time while the drum is stopped. Therefore, each step should be completed within the same period of time. Further, because each step is carried out while the photosensitive resin plate and the means for the treatment of each step is in one fixed position, it is difficult to effect the treatment of each step uniformly. In addition, the photosensitive resin plate is removably set on the drum by means of electromagnets and only up to 3 sheets of photosensitive resin plates can be treated per one rotation cycle.